whenever i read or see the financial news i hear about these "interest rates" that the fed sets.
1) what are these federal reserve interest rates for?
2) why does the fed set interest rates? why not set the rates permanently?
3) does the fed print money out of "thin air" or does the bureau of printing & engraving print the money?
please explain it as clearly as possible because i am economically ignorant and please do not post links to other sites explaining it because they don't really explain it as easily.